Thunder Afloat

John Thorson

Wallace Beery

'Rocky' Blake

Chester Morris

Susan Thorson

Virginia Grey

District Commander

Douglass Dumbrille

U-Boat Captain

Carl Esmond

'Cap' Finch

Clem Bevans

Milo

John Qualen

Ives

Regis Toomey

German U-Boat Officer

Henry Victor

Admiral Ross

Addison Richards

U-Boat Petty Officer

Hans Joby

Ensign Dyer

Henry Hunter

Admiral Girard

Jonathan Hale

Recruiting Officer (uncredited)

Leon Ames

Fisherman (uncredited)

Arthur Belasco

Fisherman (uncredited)

Joseph E. Bernard

Recruiting Officer (uncredited)

Wade Boteler

Fisherman (uncredited)

Al Bridge

Listener (uncredited)

Rand Brooks

Radio Operator (uncredited)

Don Castle

Sailor (uncredited)

Jack Chapin

Lieutenant (uncredited)

Tom Chatterton

Captain (uncredited)

Jack Rube Clifford

Man with Finch (uncredited)

Jules Cowles

Mrs. Gill (uncredited)

Leigh De Lacey

Fisherman (uncredited)

Joe De Stefani

Petty Officer (uncredited)

Edgar Dearing

Lookout (uncredited)

Richard Elmore

Recruiting Officer (uncredited)

Frank Faylen

Survivor (uncredited)

Budd Fine

Lookout (uncredited)

Allen Fox

Sailor (uncredited)

Frederick Lee

Fisherman (uncredited)

Eddie Hart

Fisherman (uncredited)

Edward Hearn

Surgeon (uncredited)

Howard Hickman

Fisherman (uncredited)

Earle Hodgins

Wireless Operator (uncredited)

Clarke Jennings

Boy (uncredited)

Payne B. Johnson

Signalman (uncredited)

Charles Jordan

Sailor (uncredited)

Lew Kelly

Fisherman (uncredited)

Jack Kennedy

Fisherman (uncredited)

Milton Kibbee

Nurse (uncredited)

Claire McDowell

Radio Operator (uncredited)

Larry McGrath

Orderly (uncredited)

Roger Moore

Fisherman (uncredited)

Philip Morris

Naval Aide (uncredited)

Forbes Murray

Old Sailor in Bilge Area (uncredited)

Frank Orth

Wireless Operator Sending Coded Message (uncredited)

Syd Saylor

Engineer (uncredited)

Harold Schlickenmayer

German Operator (uncredited)

Ferdinand Schumann-Heink

German Sailor Looking for Wireless (uncredited)

Hans Schumm

Cook on Tugboat (uncredited)

Harry Semels

Sailor (uncredited)

Lee Shumway

German Sailor (uncredited)

Robert R. Stephenson

Shore Patrol Sailor (uncredited)

Harry Strang

Young German Sailor (uncredited)

Walter Thiele

Junior Officer Standing by Map (uncredited)

Emmett Vogan

German Officer (uncredited)

Wolfram Von Bock

German Sailor (uncredited)

Hans von Morhart

Sailor (uncredited)

Doodles Weaver